Telecommunication and data services are becoming increasingly sensitive to interruption in service. Service providers, for example, strive for minimum network service disruption. Conventional mechanisms for performing line card upgrade on physical routers, however, results in traffic disruption for a long duration (typically for a few minutes). For example, a conventional method for upgrading a line card on a physical router may include downloading a new image on the route processor (RP) currently serving as a standby supervisor for the physical router (herein referred to simply as the standby RP). The configuration and operational state is then copied from the RP currently serving as the active supervisor for the physical router (herein referred to simply as the active RP) to the standby RP. The RPs are then configured to swap roles (i.e., the active RP becomes the standby RP, and the standby RP becomes the active RP). Next, the new image is downloaded onto the new standby RP. Finally, the RP roles are swapped back to their original configuration.
Under a conventional upgrade process, traffic loss is prevented by redirecting traffic to a secondary physical router while the upgrade is being performed. For example, the physical routers can be operating in Inter-chassis redundancy (ICR) mode. This requires, however, duplicate data ports to source incoming traffic and redundant hardware of the same type (for each chassis to be upgraded), which makes it an expensive solution.